6 THE VOYAGE OF H.M.S. CHALLENGER. 



They are reproduced both in the Narrative of the Cruise (vol. i. jrt. ii. p. 831) and 

 on PL I. fiofg. 1-3. There is no trace of longitudinal lateral slits — so characteristic of 

 the Schizonemertea — but a terminal crescentic groove (marked out by darker pigment and 

 by more profuse ciliation in one of the two specimens) was present in both. The pro- 

 boscidian opening could be easily detected in both specimens, the subtermiual mouth in 

 one of them. 



Incomjslete as was the information that could be gathered from superficial examina- 

 tion, very interesting data came to light after the two specimens had been transferred to 

 the microscopic slides. From specimen a, which was dredged at Station 45, a con- 

 tinuous series of transverse sections was made, whereas specimen h, from Station 47, was 

 cut transversely along the region behind the brain, nearly horizontally through the 

 brain and tip of the snout, and longitudinally through that region of the body where 

 the nephridia are found. 



It is very striking that in all these sections the cellular integument is of a consider- 

 able thickness when compared with the muscular (PI. IL; PL XL figs. 1, 2). In it we 

 may distinguish several strata successively characterised (PL IV. fig. 1) by an accumu- 

 lation of nuclei, by profuse integumentary gland-cells, &c., which will be more fully 

 described in another chapter of this Report. 



Curiously enough the contents of the deeper glands have a well-marked green 

 colour in the anterior portion of one of the body fragments of specimen h, whereas 

 they are brownish-red in the posterior portion, the w^hole fragment having first been 

 stained with picrocarmine. 



A homogeneous basement-membrane separates the integument from the subjacent 

 muscles. This membrane is more deeply stained than other portions of the intercellular 

 substance and thus stands out very clearly. 



In the outermost cellular layer, distinct unicellular, flask-shaped glands are present 

 (PL IV. fig. 1), although they are not so numerous as in many Schizonemertea, These 

 facts authorise us to look upon the integument of Carinina as similar in all its 

 essential elements to that of other Nemertea. We will further insist upon this similarity 

 when describing Etipolia and Cei^ebratultis. 



Before we pass from the integument to the muscular investment of the body we have 

 to mention the central nervous system, which is found outside the homogeneous basement 

 layer just referred to. Where the tissue of brain and nerve-stems takes its course in 

 the deeper layers of the integument, it is directly applied against the subjacent muscles, 

 the basement-membrane being indistinct if not interrupted beneath these central parts of 

 the nervous system (PL III. fig. 7). 



In addition to the two lateral stems, each transverse section reveals the presence of a 

 dorso-median thinner nerve-stem, corresponding to what I have formerly termed the 

 proboscidian sheath-nerve. 



