1 1 



I. Nannastacus Hanseni n. sp. (Text-fig. i, a — e). 



Description of adult Male. Total length 1,5 mm. 



Carapace about two-fifths of total length, broader than deep, dorsal surface depressed 

 in the middle line between the swollen branchial regions and elevated posteriorly into a bilobed 

 prominence which overhangs the succeeding somites. Pseudorostrum, seen from the side, hori- 

 zontal, truncate. Antero-lateral angle slightly produced forwards, bluntly pointed and obscurely 

 serrate. Seen from above the pseudorostral plates do not meet either above or below the 

 respiratory channel. The eyes are large, each with three hemispherical corneal lenses. The 

 surface of the carapace, especially on the dorsal side, is beset with low, rounded tubercles. 

 Laterally these pass into smaller granulations and near the lower margin the surface is rugose. 



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Fig. I. Nainias/aciis Hanseni n. sp., adult male. 



a. From the side. b. Fiom above, c. First abdominal somite from the front. 



d. Fifth leg. c. Last somite and Uropod. 



The first leg-bearing somite is very short and hardly visible from the exterior. The 

 last three thoracic somites have each on the dorsal surface a pair of prominences beset with 

 tubercles and spines. These prominences are largest on the last somite where they resemble 

 the prominences of the abdominal somites. The pleural plates of the leg-bearing somites are 

 slightly expanded and the whole surface is roughened with granules. 



The abdomen is little more than ^,'4 of the length of the cephalothoracic region and the 

 fifth somite is hardly longer than the preceding. The first four somites each bear on the dorsal 

 surface a pair of stout sub-cylindrical processes, beset with tubercles, and terminating each in 

 a stout spine (text-fig. i c). The height of the processes of the anterior somites, measured to 



