hoyle: reports on the cephalopoda. 59 



I. INTEGUMENTARY ORGANS. 



A. The Mantle (Plate 10, Fig. 1) : — The hinder part of the inferior surface 

 is covered by a patch of organs (])), whilst in front of this they are placed in 

 more or less regular linear series of which the following may be distinguished : 



1. A double row (m^) placed not very far from the median ventral line on 

 either side and leaving a narrow free space between them. 



2. A single irregular series (/«-) a little distance to the outer side of each 

 of these. 



3. A fairly regular single series which commences on either side at the 

 prominent angle of the mantle-margin and passes backwards, converging 

 towards the median line in its course (to*). 



All these six lines pass posteriorly into the patch of organs above mentioned. 



4. Still further to each side is a wavy series of small organs more irregular 

 and more widely spaced, extending nearly to the posterior extremity of the 

 body, whilst dorsall}^ to these again and situated on each side of the mantle, is 

 a row of about half a dozen. 



5. Along the margin of the mantle is a single series extending rather more 

 than halfway round (ni*). 



On the dorsal' surface I detected only two or three minute organs, in a 

 linear series parallel and near to the dorsal median line. 



B. The Siphon (s) : — On the ventral face of the siphon are two groups, 

 one on each side, leaving a clear space in the middle between them. Each, 

 group is roughly triangular in arrangement "and consists of six to ten organs. 



C. The Head : — The inferior surface of the head presents a brilliant array 

 of these little organs. Most conspicuous perhaps is a longitudinal series occu- 

 pying the median ventral line (/(•). Anteriorly this series bifurcates to pass 

 up the fourth arm, and posteriorly it also bifurcates just in front of the tip of 

 the funnel and the two limbs pass backwards and outwards along the mai-gin 

 of the I'uimel-groove. Parallel with this median series are two othei-s, one on 

 each side (h^), which start from the line of organs along the edge of the 

 funnel-groove, and pass forwards to the outer edge of the fourth arm on each 

 side. Parallel with this line is a short row of thn-e or four organs, between 

 the funnel and the eye (/<*), and in the same line with it in front of tlie eye 

 is a group of four to eight (/<*). A semicircle of organs is found round the 

 ventral margin of each eye aperture. 



D. The Arms: — Only the third and fourth pairs of arms are provided with 

 these organs. On the fourth pair there is a single linear series on either mar- 

 gin of the ventral face. The line on the inner margin is the continuation of 

 the bifurcated median line on the lower surface of the head (/i') mentioned 

 above. It extends about halfway up the arm and then ceases. That in the 

 outer margin is u continuation of the series parallel with the median line (h^) ; 

 after passing forward a short distance it becomes discontinuous and is res>oIved 



