ELIOT — NUDIBRANCHS. 417 



spermatotheca are thick and produce a secretion. In some specimens small clumps of 

 spermatozoa are embedded in this secretion. In others all the spermatozoa form 

 a central mass in the main cavity of the spermatotheca. It is possible that the 

 secretion serves to form small packets of spermatozoa or spermatophores. The 

 spermatotheca communicates by a long thin duct with a vaginal opening which lies at 

 the base of the penis. The other division of the female branch enters the mucus * 

 gland, enclosing the albumen * gland, which is smaller. The mucus gland communi- 

 cates with the exterior directly by a slit-like irregular aperture which lies a little behind 

 the other orifices and is much larger than they are. Only spermatozoa are to be found 

 in the ducts and in the spermatotheca. There are no ova except in the hermaphrodite 

 gland, where they are in process of ripening or nearly ripe. 



In all the specimens examined microscopically were found scattered cells which do 

 not seem to form part of the essential bodily structure. They are large and rounded in 

 outline, with vacuolated contents and a lai-ge round nucleus. They occur chiefly in the 

 connective tissue spaces, in spaces hollowed out in the dermal muscle layers and among 

 the epidermal cells. The fact that they are absent from the cavities of all the internal 

 organs and from the lacunar blood spaces, and that they are limited to the dorsal regions 

 of the body which are of a deeper green than the ventral surface, suggests that they are 

 of the nature of Zoochlorellce or symbiotic alg?e. 



It will thus be seen that I>oridoeides is an annectant form connecting the Holo- and 

 Cladohepatica. It has the essential features of the latter, for its liver-system is clado- 

 hepatic, there is no blood-gland, only one spermatotheca, and the anus is lateral. On the 

 other hand, the shape is doridiform, except that there are no gills whatever, and the 

 genital system is triaulic. 



2. Pteraeolidia annulata, sp. nov. (Plate 25. fig. 13.) 



(For genus, see Bergh, Beitr. zur Kennt. der Aeolidiaden, iii. p. 22, and Eliot, in Proc. Zool. Soc. 

 1903, vol. i. pp. 255-6.) 



Label : " S. de Malha. 12, fath. 47." 



One specimen nearly rolled up into a ball, but 35-40 mm. long if stretched out. 

 Maximum breadth across the back 4 mm. The body is bluish white. The cerata are 

 of much the same colour, but bear below the tip of each a single very distinct ring of 

 carmine. The tips themselves are vivid white. The oral tentacles and rhinophores are 

 carmine. There are no marks or mottlings on the body, but the white foUicles of the 

 hermaphrodite gland are visible through the dorsal integuments. 



The foot appears to have had tentacular angles in front, but is so much contracted 

 that its structure is uncertain. The oral tentacles are short distinct columns rising 

 from an oral veil. The rhinophores are distinctly perfoliate. The cerata are arranged 

 as is usual in the genera Flabellina and FteraeoUdia, and are set in eleven fairly distinct 

 groups. The first group consists of two rows, the others of a single row only. In the 



* The functions of these glands are presumably as indicated by their names, but it is not easy to say which 

 is which. 



