Mr. H. J. Carter on the Spet'matology of a new species of Nais. 23 



of the reproductive band; oviducts aud ovisacs in bunches 

 under and posterior to it respectively ; openings of testicular 

 sacs undiscovered, those of the oviducts ventral, and passing 

 through the reproductive band. Spermatozoon (fig. 34) capi- 

 tate, straight, the anterior thii-d or head uniformly enlarged, 

 twice or thrice the thickness of the rest, pointed ; the posterior 

 two- thirds gradually alternated to the extremity ; total length 

 l-700th of an inch. Segmental organ double in each seg- 

 ment, with the exception of those under the reproductive 

 band. Floating-cells of the peritoneal cavity colourless, oval, 

 fusiform. Blood colourless. Length of body when dry, a 

 little more than l-5th of an inch. 



Hab. Living and breeding in the portions of Glceocapsa which 

 grow on the sides of gutters and old walls during the rainy 

 monsoon only. 



Loc. Island of Bombay. 



Obs. — This species also belongs to the genus Blanonais, if it 

 be not absolutely necessary for this, that the hairs of the cirrus 

 should end in hooks. 



Having thus premised the specific and general characters of 

 these worms, the reader will be prepared to follow the other 

 observations on them to which I have alluded, hi doing this, 

 however, it is desirable that he should remember that they will 

 be entirely confined to Nais fusca, except where, for confirmation 

 or to fill up lacuna, it may be necessary to refer to those sup- 

 plied by N. albida. 



Integument. 



The integument of Nais fusca may be stated to consist of two 

 transparent, cylindrical sheaths or layers (fig. 3 r, s), of which 

 the outermost is composed of cells, and the innermost without 

 apparent structure. Within the latter, again, floats the aliment- 

 ary canal (which may be viewed as a third cylinder) and the 

 other internal organs of the body. 



In the cells of the outer or dermal layer, there is nothing 

 remarkable except the reproductive band (fig. 3 /), which espe- 

 cially claims our attention, because it will hereafter be seen to 

 be developed in proportion to the presence of spermatozoa in 

 the so-called " testes,^^ and therefore may perhaps be found to 

 furnish the sperm-cells of these organs. 



This band seems to be merely formed by an hypertrophy or 

 inflation of the dermal cells of this part, which, having become 

 distended with vesicles filled with refractive matter (fig. 5), pre- 

 sent individually the following composition from without in- 

 wards (fig. 5 c) : viz. a delicate cell-wall, more or less partially 



