442 G. 0. SARS, 



9. Amathillina spindsa, Grimm. 



(PI. 4, figs. 7—16). 



Amathillina cristata, var. spinata, Grimm. MS. 



Specific Characters. — Body agreeing iu form witli A. cristata, l)iit hav- 

 ing tlie back distinctly carinated througliout, all the segments of mesosonie 

 and metasome being elevated to well-defined triangular expansions increa- 

 sing in size posteriorly, the hindmost not differing iu shape from the others. 

 First segment of nrosome with a small rounded expansion doi'sally, the 

 other 2 carrying a number of minute hairs at the hind edge. Cephalon with 

 the lateral lobes somewhat prominent, and transversely truncated at the tip. 

 Coxal and epimeral plates about as in A. cristata. Eyes reniform and some- 

 what obli((uely disposed. Antennae and gnathopoda nearly agreeing in struc- 

 ture with those parts in A. cristata. Pereiopoda rather slender, and having 

 their outer part densely clothed with fascicles of slender spines, basal joint 

 of the 3 posterior pairs in both sexes less exi)anded than in the type species. 

 Uropoda and telson not differing essentially from those parts in A. cristata. 

 Length of adult male 25 mm. 



Bemarks. — This form would seem to have been regarded by Dr. Griram 

 as only a variety of ^. cristata, since most of the specimens have been labelled 

 A. cristata, var. spinata'^]. In my oi)inion, it ought, however, to be regarded 

 as a distinct, though nearly-allied species, differing, as it does, from the 

 typical form, not only in its much larger size, but also iu some structural 

 details, for instance, in the much more fully developed dorsal crest, and iu 

 the hindmost dorsal expansion being triangular like the preceding ones. More- 

 over, the basal joint of the 3 posterior pairs of ])ereiopoda is in both sexes 

 much less expanded than iu A. cristata. 



Description. — Adult male specimens attain a length of 25 nun., and 

 this form accordingly grows to a considerably larger size than the type 

 species. 



The general form of the body (see fig. 7) resembles that in A. cristata, 

 being moderately slender and somewhat compressed, with the back more or 

 less curved. The dorsal crest is, however, much more fully developed, 

 and extends over a greater part of the body, all the segments of both the 

 mesosome and the metasome being elevated to well-defined triangular 

 dorsal expansions, successively increasing in size posteriorly, and eveu 

 the 1st segment of the nrosome exhibits traces of a dorsal crest, being 

 produced in its posterior part to a small, but well-defined rounded expansion. 

 The expansion of the last segment of the metasome, which in A. cristata 



1) This adjrctive form is scarcely acceptable, and slimilfl more properly be spinom. 



*U3.-U,iT. CTp. 272. 2 2 



