132 MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 
while the two rami are more as in Petalophthalmus, though broader. The other biramous abdominal 
appendages in the Gampsonychide are truly schizopodal. 
Fic. 3a.—Telson of Peta- 
lophthlamus¢. 
Fic. 3.—Petalolphthalmus armatus<. 
$ 
Fic. 4b. — Third 
perce of Peta- 
ophthalmus 9. 
Fic, 4.—Petalophthalmus armatus?. This and Fig. 3 after W.Suhm. 
Fic. 4a.— Second gna- 
thopod of Petalophthalmus 
9. 1, breeding lamella. 
Classifying the Schizopoda by the carapace, modifying Willemoes-Suhm’s table by throwing 
out the Nebaliadew and substituting the Gampsonychida, there would seem to be three groups, as 
follows: 
Ly Oarapace absent :--< Sars kocsis s toh San seme wele nates eiciae eee Seen aieecemaan aaen wenn ane (Gampsonychide). 
Il. Carapace free, varying in 81z6_-- << 22 scase sere cena ee eee (Gnathophausia, Petalopthalmus and Chalaraspis). 
TIL. Carapace fastened. to the thorax: 5222-- en. -se eee oe one ee aes (Mysis, Lophogaster and Euphausia). 
But I should agree with Willemoes-Suhm that this is not a natural genealogical classification, 
and throwing out the Nebaliad, which, as we have endeavored to show, belong to a distinct order 
of Crustacea, the families of Schizopods may be enumerated thus (after adding the Gampsonychide 
to von Suhm’s table), all having seven abdominal segments : 
Carapace absent, six pairs of thoracic legs... 60.2. - cons sec ncs cence sascwsevsweccnce=se=nesesaess I Gampsonychida. 
Carapace well developed, six pairs of thoracic legs... ooo. coco ek ncn s cece womens eon eesnesnesse Il Myside. 
Carapace well developed, eight pairs of thoracic legs..........-..---- ------ --- 20+ eee eee eee eee Il Euphausiide. 
Carapace well developed, four pairs of thoracic legs...... 2.22... 222+ 22-2 eee ee een ne eee eee eee IV Chalaraspide. 
Carapace well developed, seven pairsof thoracic legs:........----.--------+- +--+ seee-+----------V Lophogastrida. 
When we compare the Gampsonychidw with the Synearida (Acanthotelson), we see that both 
groups have the same number of body-segments, and that both lack a carapace; and thus, while 
the Gampsonychidw are the ancestors of living Schizopods, the group as a whole probably de- 
