Gatty Marine Laboratory^ St. Andrews. 135 



^r.'ilaquin * gives also an account of the sexual and asexual 

 pliases of Sdhnacina dysteri : — 



I. I'hasc of a young i)r(jtan(lrous form. The male genital 

 segments arc incorporated with the thorax, and are sterile. 



II. Phase is that of asexual reproduction, or schizogenesis. 

 In this the animals present incomplete male sexuality, mani- 

 fested by tiie productioa of a few spermatozoa which attain 

 maturity. 



III. Phase — hermaphroditism. Gonads (male and female) 

 are situated in distinct segments — the male in the three (two 

 to four) anterior al)dominal segments, the fenuilc in the eigiit 

 to ten segments which follow. 'y^\\o. circnldtion \\\ Sa/inacini 

 and Filograna resembles that of the Ser[)ulids in the particular 

 reticulation of vessels distinct from the coelom. There are 

 branchial and ventral vessels. Around the intestine is a 

 vascular sinus, as in Serpulids and Sal)ellarians. In Stdina- 

 cina and Filof/rana this sinus lies between the endothelium 

 splanchuoplauique of the cadom and tiie intestinal epi- 

 thelium. This part of the hicmocele represents exactly the 

 primitive blastocoele. 



The same author f (1911) gives an elaborate disquisition 

 on the phases of Salmacitia, grouping them as follows : — 

 I. The sexual forms, including the young protandrous forms, 

 with three to five segments iu the thorax, two intermediate, 

 and six abdominal segments. II. The unisexual, rarely 

 female, less rarely male. The female is 2^ mm. long, with 

 three thoracic segments, an intermediate asetigerous segment, 

 and six to eighteen abdominal distended with ovocytes. 

 Probably this becomes hermaphrodite. The male is IJ- 

 2^ mm., with seven thoracic segments, sixteen ripe abdo- 

 minal segments, and three or four terminal. 



The hermaphrodites have eight branchiae, eight thoracic 

 segments, then two or three achetous segments ; immediately 

 behind arc two or three with male gonads, and the succeeding 

 ten have female gonads with rod ova. They reach 6-7 mm., 

 and may have fifty abdominal segments. In some herma- 

 phrodites male elements predominate, the female segments 

 being reduced. In others a hermaphrodite segment occurs at 

 the limit of the male region, the male elements being on one 

 side, the female on the other. He has also seen a herma- 

 l)hrodite gonad. 



The mctamere, as a rule, is nnisoxual, but, as mentioned, 

 between the male and female regions a hermaphrodite one 



• Assoc. Frnn^aise .\ilv. Sc. Lille, V.Od, p. 135. 



t y.nn]. An/.i '.T. fM. ^vwii. p. I'Ol. 



