25 



are short, slightly decrease in length from the first to the last which comes suddenly to a sub- 

 acute incurved point forming a sort of claw, are curved, fringed on their inner and concave 

 margins with cilia and minute spinules, and capable of being coiled tightly together so as to 

 form a prehensile organ. 



The oculigerous somite has its anterior margin straight, and is but faintly con- 

 stricted in front of the eye-tubercle. 



The first thoracic somite, if its distinctness from the oculigerous somite be admitted, 

 is very short. Of the remaining somites, the second and third are subequal, the former being 

 if anything the longer; are as perfectly cylindrical, and nearly as long as, but slightly stouter 

 than, the filiform proximal moiety of the rostrum; and suddenly expanded at their articular ends, 

 each somite presenting the appearance of a cylinder with a greatly truncate cone affixed by its 

 truncated surface to each end. The fourth and last somite is scarce half the length of those 

 that precede it, and is similarly expanded at its anterior end only. From the sides of the 

 expansions at the posterior extremity of the second and third spring two somewhat inflated 

 outwardly-directed, obconic processes which might, at first sight, be mistaken for the first of the 

 basal joints of the legs from their close similarity to these, but which are in reality one with 

 the somite from which they arise; precisely similar processes carry the legs both of the first 

 and of the last somite in which, however, they diverge like the arms of the letter Y. Wedged in 

 between the roots of these processes of the last somite and the posterior boundary of its ventral 

 are, lies a minute, obtusely conical tubercle with a large circular (anal) aperture at its extremity. 

 This is the abdomen, a very evident, though rudimentary, strueture in most Pycnogonida. . . 



The legs are long, slender, simple, equal in length, rather more than twice as long as 

 the body including the rostrum, and are composed of eight joints, terminated by a weak, 

 slightly curved claw. Their three basal joints are as broad as long, equal, and almost globular-, 

 the fourth is club-shapeel at the distal end; the fifth is all but as long as the fourth and, with 

 the remaining joints, perfectly filiform; the sixth is shorter and about twice the length of the 

 two last together; these are subequal. 



Length of the body including the rostrum ... 13 mm. 



Length of the legs, including the rostrum . . . 26 mm. 



Length of the 2 nd pair of cephalic appendages. . 10 mm. 



Length of the 3 rd pair of cephalic appendages. . 1 2 mm. 

 From the linear form of the body and the slenderness of the legs, I conclude that my 

 speeimen is a male, . . . 



Hab. Dredged by the writer at Port Blair, Andaman Islands, in 25 fathoms of water, 

 at which depth the bottom was clothed with a dense tangle of delicate, filamentous algae so 

 closely resembling the animal in point of colour and form, that the latter was with difficulty 

 distinguishable". 



(Diagnose nach Wood-Mason, Journ. Asiat. Soc. Bengal, V. 42, 1873, p. 172). 



Die meisten Autoren (nur Miers und Carpenter nicht) stellen RJiopalorhynchus einfach als 

 Synonym zu Colossendeis. Durch den Fund zahlreicher Exemplare aus dem malaischen Archipel 



SIKOGA-EXPEDITIE XL. 4 



