TO. 1151 /I MKIUCA N MLROCnETA—COOK. 4(j 1 



Ueput^riatoiial pores wanting. 



8ui)j>Iftin<;ntary margin rathor long, of rather firm and even texture, 

 and (juite entire. 



Last segment Hubsemicircular, broa<ler than the carina- of segment 

 10; broader and shorter tlian the last segment in Cyclodesmidaj and 

 iJesrnonida'; [josterior margin an even, tliin edge. 



Copulatory legs of tyj>ical genus, simple, falcate. 



This family may be understood to fjonsist for present purposes of the 

 monotypic genus SplifrriofleHmntf, the se<;ond supf>osed .-pecies of whi(-h 

 is certainly generically distinct and probably does not belong in the 

 ])resent family, as is i>ointed out below. 



In SpliffriofhsmiiM the body cavity is distinctly more flattened than 

 in the other glomeroid families, and the carina- are deiMirved so as to 

 jiroject far below the ventral [>lane of the body cavity. This feature 

 reaches perhaps its highest <levelopment here, and is (xnTclated, as in 

 similar forms, with more slender legs than the otherwise robust body 

 would lead us to expect. It will be understood that, as these animals 

 coil up, their legs may not be too bulky, and as the carina- project far 

 downward, tlie legs must have Wiusiderable length so as not to be inter- 

 feied with in crawling. 



The anterior segments are sri entirely different from those of other 

 families that the supposition of the independent acquisition of this pro- 

 vision for coiling uj) seems to be the only possible e\i)Iariation, for it is 

 well-nigh unthinkable, or at least violently unieasonable, to suppose 

 that adaptation for this means of defense having been ac^juired by the 

 enlarg«-ment, say, of the third segment the mf)difi<;ation should have 

 j;radually been transferred to the fourth, for during the process of 

 change the efficiency of the arrangement would have been destroyed. 

 The form of the copulatory legs, the proportions of the antennal Joints, 

 together with the form of the segments as referred to above, are in the 

 lii e of the view that HpkariodeiimKH at least has no tangible relation- 

 ship with the other glomeroid types of Merocheta, If this be a^imitted, 

 the similarity in form of the posterior segments of the body in this 

 family, the Cyclodesmida- and Desmonida;, must be looked upon as an 

 instance of strikingly close ai)pioximation. We have, however, only to 

 bring into the c^ompariwjn the several genera of Oniscida*, which have 

 taken on practically the safne form, to realize that the i)0ssibdities of 

 apfnoximation are great enough to be taken into account far more widely 

 than is customary among systematists. 



Genus SPH>ERIODESM US Peters. 

 filomeridenmiiH HAVHt^rUK, Liiinsffa Kritorn., ]HT)H, XIII, p. '{2S; not (iloriuriileiimuH 



SphtyriodeHmuH I'ETKlsh, MonatHbcr. K. I'iciihh. Aku<l. VVihh. lierliti, 1801, ji. 529. 



