APPENDIX. 



Additional Note on Typhlotanais brachyurus. 



I have already [supra, p. 123) described this Isopod from three specimens dredged 

 at Station 246, which were mounted on a slide during the expedition. I have since 

 received a number of other specimens found during the examination of the deposit from 

 the same locality, which agree in structure with the first received specimens, and must be 

 referred to the same species. The latter specimens were in every case enclosed in a tube 

 averaging about 14 mm. in length; the animals themselves are considerably shorter than 

 the tube which they inhabit, and were usually found at one end where the base of the 

 tube is rather narrower than at the other end. The tube is shaped somewhat like the 

 shell of Dentalium, being slightly curved, and narrower at one extremity than the other. 



The tubes are of a darkish brown colour and are very tough; they are composed of 

 fine mud, enclosing larger particles, and occasionally, on the outside, shells of Globigerinse; 

 the mud is compacted together by a tough secretion which seems to have no structure. 

 When the Crustacean is extracted by cutting up the tube longitudinally its cut edges 

 become folded in. It is possible that the tube is not manufactured by the Crustacean but 

 has been originally formed by some Annelid. Against this supposition may be urged the 

 fact that the tubes were more or less uniform in size, and were exactly fitted to the 

 elongated body of the Crustacean, the wider anterior- portion serving to render the 

 movements of the ehelipedes possible, and also to lodge the wider cephalothorax ; the 

 tapering form of the tube in fact corresponds to the tapering form of the Isopod. More- 

 over the formation of a tube-like dwelling is known to occur in other Tanaids as well as 

 in many Amphipoda. There is a general account given in Bronn's Klassen und Ord- 

 nungen des Thierreichs x of the tube dwellings of certain Tanaids and Amphipoda, to 

 which reference may be made for information on the subject. 



Ischnosoma thomsoni, n. sp.* (woodcut, fig. 1). 



The single specimen of this species measures 6 mm. in length ; it is a male. 



The anterior region of the body, comprising the head and first four segments of the 



1 Bd. v. Abth. ii. Lief. 16, 17, p. 435. 



2 Named after Mr. G. M. Thomson, well known for his work among the New Zealand Crustacea, particularly 

 Isopoda. 



(ZOOL. CHALL. EXP. PAET XLVIII. — 1886.) Bbb 22 



