On the Osteology of the Order Opisthomi. 217 



slightly curved upwards, about three and one-halt" times as 

 long as the head ; closely set with moderately long setu3 to 

 liie distal tifih. Terniinul hairs very short. 



IJab. India ; four specimens, together with several nymphs 

 and pupa, taken by Mr. Iyer on " Piaman " leaves at Karwa- 

 jianny, West Deiua Dun, base of the West Himalayas. 



P. coriaceus much more nearly approaciies the South 

 African species caudatuSj Bagn., tiian the Malayan gracilis, 

 iJagn. It is a smaller species, tlie head is much shorter and 

 broader, and the surface is roughly sculptured, either reticu- 

 late or tiuely scabrous; the abdominal segments are strongly 

 transverse, whilst the tube is, compared with the length of 

 head, even longer than in caudutus. 



The discoveiy of caudutus and this species, which in the 

 form of the abdomen differ strongly from the type ^?-«ci7i6', 

 would seem to show that the genus Panurothrips has stronger 

 atfiuities with the Phloeothripidm than with the Idolothri[)ida3. 



XX. — The Osteology of the Teleostean Fishes of the Order 

 Opisthomi. By C. Tate Regan, M.A. 



(Publislied by permissiou of the Trustees of the British Museum.) 



The order Opisthomi comprises the single family Mastacem- 

 belidse, with two genera, Mastacemhelus and lihynchohdella, 

 from the fresh waters of Africa and Southern Asia. These 

 fishes have the body elongate and compressed, covered with 

 small scales ; tiie many-rayed dorsal and anal fins are con- 

 tiguous to or confluent with the small caudal ; the dorsal is 

 preceded by a series of isolated spines and the anal has three 

 spines, the second strong and depressible in a groove ; the pec- 

 torals are well developed, but the pelvic fins are absent. The 

 mouth is small or of moderate size, terminal or subterminal, 

 with villiform teeth in the jaws and sometimes on the vomer; 

 the maxillaries are firmly attached to the non-protractile prse- 

 maxillaries. There are two nostrils on each side, the poste- 

 rior in front of the eye, the anterior tubular, at the side of a 

 fleshy tentacle at the end of the snout. The gill-membranes 

 are separate or narrowly united, and free from the isthmus, 

 but the gill-openings are restricted from above, the oper- 

 culum having no free edge. 



Such are the principal external characters of this group 

 of apodal acanthopterous physoclists ; the skeleton indicates 



