248 KMBIOTOCID^. 



8. Ditrema aggregatum 



Micrometrus aggregatus, Gibbons, Proc. Acad. Nat. Sc. Philad. 1854, 



p. 125 ; Agass. Proc. Bust. Sac. Nat. Hist. 1861, p. 128. 

 Cymatogaster aggregatus, Gibbons, I. c. p. 106. 

 Ilolconotus rhodotenis, Girard, Proc. Ac. Nat. Sc. Philad. 1854, pp. 141, 



152; 1855, p. .'322; U.S. Pacif. R. R. Exp. x. Fishes,^. 19.3. pis. ,35, .36. 



tigs. 1-4*, pi. 26. figs. 7 & 8 • Suckle)/, Nat. Hist. Wash. Terr. p. .358 ; 



(not Af/ass.). 

 Metrogaster aggi-egatus, Agass. I. c. p. 133. 



D. ^^. A. ^^. L. lat. 40-44. L. transv. 4/12. Vert. 17/20. 



The middle dorsal spines are longer than the posterior. Scales on 

 the cheek in three series. The height of the body is two-fifths of 

 the total length (without caudal). Jaws equal in length anteriorly ; 

 lips thin, the fold of the lower being continuous round the jaw. The 

 maxillary does not quite extend to the anterior margin of the eye. 



a. Adult. San Francisco. Froni the Boston Museum. 



h-c. Half-grown. Humboldt's Bay. Presented by the Smithsonian 

 Institution. 



d. Fine specimen. New Orcas Islands. Presented by the Lords of 

 the Admiralty. 



e-h. Males and pregnant females. From the Haslar Collection. 



i-l. Adult : skins. Esquimault Harbour, Vancouver Islands. Pre- 

 sented by Earl Russell. 



m. Adult: skeleton. Humboldt's Bay. Presented by the Smith- 

 sonian Institution. 



9. Ditrema brevipinne. 

 D. ^. A. |. L. lat. 45. L. transv. 4/12. 



The three posterior dorsal spines are the longest, a litde shorter 

 than the anterior rays. Scales on the cheek in two series. The 

 height of the body is one-third of the total length (without caudal). 

 Jaws equal in length anteriorly ; lips thin, the fold of the lower 

 being interrupted in the middle. The maxiUary does not quite 

 extend to the anterior margin of the eye. 



Vancouver Islands. 



a. Seven and a half inches long : skin. Esquimault Harbour. Pre- 

 sented by Earl Russell. 



We would add to the above diagnosis : Head somewhat longer than 

 high, its length being nearly one-fourth of the total (without caudal). 

 The upper ])rofile is somewhat concave above the eye. The diameter 

 of the orbit equals the extent of the snout, and is two-sevenths of 

 the length of the head. Cleft of the mouth oblique ; teeth rather 

 small, in a single series. The scaly part of the cheek is narrower 



* If the figure of pi. 36 has really been drawn from a specimen of this species, 

 the control OTer the artist must have been very careless, the scales being repre- 

 sented much too small. 



