254 bulletin: museum of compaeative zoology. 



in width. When partially contracted the body is short and com- 

 pact, as in A. angidatus. 



Color. — In the alcoholic specimens the whole surface of the 

 body is dark mottled brown, the color consisting of innumerable 

 dark dots which run together, forming irregular blotches. The 

 dark markings are so closely placed as to nearly obscure the ]>aler 

 ground color. The mottling is less complete on the ventral surface, 

 so that the ground color is revealed. The pigment resides wholly 

 in the integument, and is easily removed by rough handling. 



Ocelli. — The eyes are arranged in two groups on each side of 

 head, and are of fairly large size. An anterior, marginal group of 

 10-16 ocelli on each side is arranged (when the head is extended) 

 in an irregular row which becomes broken up posteriorly into an 

 irregular cluster (PL 21, ligs. 129, 130). The posterior, or cerebral 

 groups each consist of about 3 to 6 ocelli overlying the brain. 

 When the head is contracted the marginal groups of ocelli consist 

 simply of irregular clustei's reaching inward well toward the median 

 line. 



Proboscis. — Proboscis sheath extends nearly the whole length 

 of the body, as described below. Proboscis large ; when extruded 

 it is often more than three fourths the length of the Avhole body ; 

 withoiit color after i»reservation ; often everted when animal is 

 killed. 



There are two pouches of accessory stylets, with 5, 6, 8, or more 

 stylets each (PL 24, fig. 194). These are dagger-slia})ed and sym- 

 metrical, with cores of granular nature, covered with a clear and 

 homogeneous sheath (PL 21, figs. 137, 139, 140). They measure 

 with great constancv about .234 mm. in length by .024 nnn. in 

 width in their middle i)ortions. 



The central stylet is exactly similar in size and shape to the lat- 

 eral stylets. The basis is barrel-sha})ed (PL 21, figs. 136, 138), but 

 is slightly broader at the end farthest from the inseition of the sty- 

 let. The basis is remarkably short and thick, being less than half 

 the length of the stylet itself. It measures but 0.105 mm. in length, 

 and is 0.075 mm. wide at its posterior end. 



The proboscides of six individuals were sectioned. Of these, 

 four were provided with 13 nerves each, while each of the two 

 others had but 12. The nerves were rather large and conspicuous; 

 muscular and epithelial layers as in other species. 



