370 CHAS. CHILTON. 



the pleon than in existing species, but this is probably 

 merely the result of compression, which would produce a 

 greater effect on the subcylindricai peraeon segments than 

 on those of the pleon, since this is already considerably 

 flattened in the living animal. 



The following measurements may be given in addition to 

 the description: — Total length of impression 18 mm., so that 

 the whole animal would have measured probably about 

 23 mm. Length of peraeopods 3 and 4, 4*5 mm.; of 5, 4 mm.; 

 of 6, 4*5 mm.; of 7, 5 mm. Depth of peraeon segments 

 3 mm.; depth of pleon segments 5 mm. (? or more). 



On the block that bears Specimen 1 there are also two 

 imperfect impressions, but they do not show any additional 

 details. 



Specimen 2, Fig. 2, a and a. (Block 240, the larger 

 impression, with its counterpart on Block 241). 



This specimen is considerably larger than specimen 1, the 

 total length of the impression being 23 mm. It shows 

 apparently the five or six posterior segments of the peraeon, 

 with portions of the corresponding peraeopoda, and the 

 first five pleon segments, the fifth being more or less 

 imperfect ; the total length of this animal would therefore 

 probably have been about 30 mm. The peraeopoda are less 

 distinctly shown than in specimen 1 ; but, as in that 

 specimen, the three posterior ones are directed backwards 

 and the anterior ones forwards. Of peraeopod 2 only one or 

 two of the basal joints are shown indistinctly. Peraeopod 

 3 shows portions of the basis and three other joints, 

 apparently merus, carpus and propod. Peraeopod 4 is 

 similar, but less distinct. Peraeopods 5 and 6 appear to be 

 overlapping, and are not distinct, though the broadened 

 basal joint is pretty clearly shown. Peraeopod 7 is more 

 distinct, and shows a structure apparently corresponding 



