1、强棘红螺的产卵期与红螺Rapana thomasiana者相同,是在每年6——8月。产卵盛季在7月下半月。产卵时所需水温为20°—26℃,最适宜水温为23°—25℃ 。 2、雌雄成体螺于产卵前1——2日先进行交配。参加交配的两个体并元身体大小的比例关系。作者于1954年7月曾在青岛水族馆发现一雌性强棘红螺与一雄性红螺进行交配,但未能观察其产卵与胚胎发育。此种杂种交配的情况过去尚无人报告。从能够进行交配以及在生殖、产卵、和卵子发育方面的相似来看,上述两种红螺的种间关系值得重新加以研究。 3、于生殖季节内,雌螺多在黎明前后开始产卵,少数在下午或其他时间开始产卵。在正常情况下,成体螺一次将卵产完,但产卵历时长短(一般为1——2月)和卵袋产出数目多寡,均与雌螺大小成正比关系。最小而能够产卵的雌螺的壳高为50毫米。 4、在产卵期间,每一母体的输卵管外套段内有1——2个卵袋同时在形成着。由同一母体所产出的卵袋,以产出的先后不同,而有不同长度,先产者较短,后产者较长。同时由于此长度的不同,各卵袋中所含卵子数量又有多寡之分。不过,尽管有上述各种不同,但同一袋内所有卵子均可进行分割并发育为幼虫。 5、强棘红螺卵子早期分割的形式,与红螺者完全相同,舆两种织纹螺Nassamutabilis,Nassa reticulatus者

Rapana pecheliensis,being amongst the largest rachigloseans found on the north coast of our country,is of high value in fishery.Tehang-Si described the general features aud the form of egg capsule of this snail in 1936 and 1955 respectively,but its life history so far is known,has escaped investi- gation.The present paper is to report the reproduction and embryonic development of this animal and tends to give a closer comparison in these respects between it and other rachiglossans ever studied.In the past four years,in addition to the trac ment of cell lineage and of morphogenetic process of embryonic stages data bearing upon the breeding season,sexual activities and spawning habit were collected.The breeding season of R.pecheliensis,like that of its sister species,R.thornasiana,lasted from the begining of June almost to the middle of August.Nevertheless this period eeemed to be affected by changes of temperature.During spawning,groups of eggs,after being fertilized one after another in a chamber just posterior to the pallial oviduct,were extruded into the latter where they became encapsulated.In the whole lumen of this duct of a female with her shell over 7.6 m.m.in height,usually no lees than two to three capsules being in formation might be found at a time,the larger and more complete one being nearer to its exit.Examinations of new-laid capsules did not reveal nurse eggs which had been found in other rachiglossans such as Purpura,Buccinum and Fasiolaria.All eggs within a capsule began to segment after the capsule was laid at temperature ranging from 21.0° to 26.5℃.The shape of blastomeres together with yolk lobe resulting from the first cleavage or the second one and the relation of cleavage plans in the later stage appeared identical completely with that of R.thomasiana,Nassa mutabilie and N.reticulatus,bnt somewhat different from that of Purpura lapillus,though in later stages of cleavage all these snails expressed an uniformity specially in the pattern of arrangement of blastomeres.Tbe presence of the yolk lobe in the first cleavage of R.pecheliensis had resulted in the formation of a trefoil btage which was very similar to that occured in the development of Ilyanassa and Dentalium.The only difference between them lies in the manner of movement by which the yolk lobe was formed.In R.pechelieusis,the yolk lobe appeared as soon as the blastomeres AB and CD were constricted off from its animal pole,while in the other two,this structure came off entirely from the vegetal pole of the egg.As cleavage proceeded a blastoderm cap came into view and when it covered three seventh of the surface of the yolk cell 4D epibolic gastrulation took place.Before the closing of the blaetopore the endoderm cells 4A.4B.and 4C.divided repeatedly to form the ventral lip of the pore.This and the delay of their becoming invested by the ectoderm cells showed that the cleavage of R.pechelienc-is was in some degree alike a meroblastic type,mostly due to the concentrating up of the yolk into 4D.Within the capsule embryos passed through a veliger stage.It was about four to five weeks from the time the ova were laid until the fully formed veligers escaped from the capsule.The organogenesis in the veliger stage of R.pecheliensis closely resembled that of Nassa reticulatus.During or just after hatching the rudiments of the osphradium,gill filaments,and heart had not yet appeared,to say nothing of that of sexual organs.