ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 745 



tubes, which are set between the dorsal surface of the animal and 

 the c£eca. The appendages of the digestive tube are continued into 

 the branchife, and the tract is also remarkable for the possession 

 of large unicellular glands with finely granular contents ; these form 

 the salivary glands. 



The male generative apparatus is composed of four pairs of ovoid 

 testicles, which are placed in the last four branchiate segments ; the 

 efferent ducts unite, on leaving the epididymis, into a short azygos sper- 

 matic canal, which passes into a large muscular pouch, into which the 

 very large penis can be retracted. The female organs consist of a pair 

 of very long pyriform ovaries, and of two delicate oviducts which pass 

 into an inconspicuous uterus. The circulatory system presents some 

 remarkable characters. There is no dorsal vessel, but there are two 

 pairs of lateral vessels, which are superposed and send branches into 

 the branchial outgrowths ; the superior lateral vessels, which may be 

 considered as being arterial, communicate with one another in each 

 ring by an annular vessel which sends fine ramifications to the surface 

 of the skin ; posteriorly, these two lateral canals bifurcate and unite 

 by the branches thus formed ; they here give off a nimiber of ramifi- 

 cations which extend over the lower surface of the sucker, and pass 

 into a double circular vessel which extends round the edge of the 

 sucker. There is a median ventral vessel which envelopes the nervous 

 system and gives rise anteriorly to a ring which communicates with 

 the lateral vessels, and posteriorly to a number of branches which 

 open into the vessels of the sucker. The nervous system has a close 

 resemblance to that of Clepsine ; there are two very large, cup-shaped 

 orange-coloured eyes. The integument, especially in the anterior 

 region, is very rich in glandular cells. 



The new genus to be instituted is called Lophohdella, and the 

 species L. quatrefagesi ; it is found in Senegambia and the rivers of 

 Africa. Its peculiarities require the formation of a now family, to 

 be called the Lophobdellidse, and placed near the Ehynchobdellidse. 



Structure of the Branchiae of Serpulacese.* — Dr. L. Orley gives 

 a detailed account of the histology of the gills in the Serpulaceae. 

 His results may be stated as follows : — 



In Serjyula the gill-threads are borne upon two curved lamellar 

 processes, one on either side of the head ; these are united by a cross 

 piece ; one or two of the gill-threads are modified into a stalked 

 opercular plate ; this latter in some species serves as a chamber for 

 the development of the ova, and is generally regarded as serving to 

 close the tube of the animal when it is retracted. Its structure, 

 however, points to the conclusion that it may also serve as a respi- 

 ratory organ (the other gill-filaments with which it is homologous 

 being chiefly tactile). It receives a vast number of capillaries which 

 branch repeatedly towards the distal end of the " cup," and end in 

 ampulla-like dilatations ; the advantage of such a structure to 

 the animal must be great, since it is enabled to protect itself by 

 closing the operculum, and at the same time the process of respiration 



• MT. Zool. Stat. Neappl. v. (1884) pp. 107-228 (2 pis.). 

 Her. 2 —Vol,. IV. 3 d 



