ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 601 



gnathopods to the feet of Nauplius or larva of the Cirrhipedia and 

 Copepoda; (4z) the digestive tract is homologous throughout with 

 that of Crustacea, particularly the Decapoda, there being no urinary- 

 tubes as in Tracheata ; f 5) the heart is on the Crustacean type as 

 much as on the Tracheate type, and the internal reproductive organs 

 (ovaries and testes) open externally, at the base of and in the limbs, 

 much as in Crustacea. 



The paper is illustrated by seven plates showing the circulation of 

 lAmulus, sections of the adult and of embryos, and details of the 

 structure of the eyes, with comparison of these with those of Trilo- 

 bites, with which group the author, as in his first memoir, allies the 

 Merostomata. 



StomatorMza of Saccnlina carcini.* — M. S. Jourdain finds that 

 these structures form delicate tubes wdth milk-white contents, which 

 ramify largely and irregularly. They form a very complex network 

 around the digestive tube, and are also found in the middle of the 

 liver ; they extend on to the genital gland, and, insinuating them- 

 selves into the muscles of the sternal region, make their way to the 

 extremities of the limbs of their hosts. That they never touch the 

 heart, the gills, or the central nervous system is probably the reason 

 why the host apparently retains its general health. They are distin- 

 guished by their opaline white colour, even in the midst of the tissues 

 •which they infest. Their sheath is hyaline and structureless, very 

 firm, and apparently formed of chitin. Near the extremity of these 

 processes there is developed a kind of sucker, which has at its centre a 

 slightly depressed orifice, corresponding to the cavity of a flask-shaped 

 body, which is, perhaps, the seat of a secretion which renders absorb- 

 able the anatomical elements on which the creature is parasitic. 



The Sacculin® are themselves the host of a species of Saccharo- 

 myces, which destroys it, and which is quite distinct from the 

 Mycoderma vini or S. cerevisice. Each of the poles of the long axis 

 of its cells gives ofi^ a myceliform prolongation. These ferment-cells 

 frequently have psorosperms associated with them. 



Vermes. 



Organization of Sternaspis scutata.f — In a second communica- 

 tion, M. Max Eietsch deals with the vascular system and generative 

 organs of this worm. 



As to the former, he finds that the dorsal vessel follows the coils of 

 the stomach ; the ventral vessel has numerous roots connected with 

 the pharynx and anterior setfe ; it runs parallel to the nerve-cord, to 

 which it gives ofi" various branches, as well as to the segmental 

 organs. Near the middle of the body it gives rise to a vessel which 

 accompanies the posterior portion of the intestine, and to two others 

 which give rise to the four genital vessels. The whole of the intes- 

 tine is provided with a very rich system of blood-sinuses, connected 

 with the dorsal and with the anterior portion of the ventral vessel. 



The genital organs have the same form in both sexes. The two 



* Comptes Kendus, scii. (1881) pp. 1352-4. f Iljid., p. 1066-9. 



