22G R. ETHERIDGE, JUN., ON A 



blackened squama? in various stages of preservation. In one 

 specimen there are a number of casts of squama? still retaining 

 in the deeper portions the remains of the blackened test. In 

 this instance they are smaller than in the former cases, mea- 

 suring only about one line by one line and a quarter. Another 

 seems to be a portion of an abdominal somite, and, if this view 

 is the correct one, that of a very large specimen indeed. As 

 compared with any of the abdominal segments of E. Scouleri, the 

 length of the specimen (more than three inches), in relation to 

 the breadth, is excessive. The anterior is clearly discernible from 

 the posterior portion by the direction of the flat squama? wherever 

 they are preserved. If an abdominal somite, the Crustacean of which 

 it formed a part must have possessed an abdomen of very differ- 

 ent form from that of E. Scouleri. On the other hand, could it be one 

 of the narrower somites near the telson of a large species, similar to 

 the smaller terminal somites in E. scorpioides, II. Woodward, from 

 the Upper Ludlow*? Another suggestion offers itself: Is it an 

 ordinary somite of large size bent down laterally, along the median 

 line ? I scarcely think so, from the apparent absence of all disturb- 

 ance of the squama?, where preserved. Or, on the other hand, is it 

 a segment of one of the smaller appendages ? Whichever way this 

 specimen may be interpreted, there is this difficulty, that, as deter- 

 mined by the direction of the squama?, the anterior end is the 

 smaller, and the posterior the larger of the two — just the contrary to 

 what we should have expected if the specimen, as we now find it, 

 really represents an abdominal somite, but as it should be if it is 

 one of the segments of the smaller appendages as represented in 

 Mr. Woodward's restoration of E. Scouleri. In the posterior cross 

 section, below the outer black crust there is visible in the fine- 

 grained matrix another black line ; the intermediate space, about two 

 lines thick at the median line of the specimen, may represent the 

 thickness of the test. The measurements are (approximately) : — 



in. lin. 



Length 3 5 



Breadth 1 



Length of largest squama?, 3 to 4 lines. 



Of the specimens collected by Mr. Macconochie, two only call for 

 special notice. The first is a cast, 1 in. 7 lin. broad, by 2 in. 6 lin. 

 long, showing spines similar to those of fig. 1, succeeded an- 

 teriorly by several series of the spine-like squama?, gradually passing 

 into the ordinary flattened scale-like squama?. The second specimen 

 is similar, but not so well preserved. The material composing all 

 the specimens, wherever preserved, is in the form of a blackened 

 shining crust or film, which is easily rubbed off and destroyed, 

 unless the specimens are immediately covered with a protective 

 preparation. Prof. James Hall t has remarked on the imbricating 



* Op. cit. pi. 29. 



t Pal. New York, iii. p. 396. 



