FAMILY SPHEZROMIDA. V7 
males of animals belonging to Cymodoce. Sphwroma 
gibbosum (M.-Edw.) and S. micracanthum (Tristan, 
M.-Edw.) are young males of Dynamene (Leach), probably 
of D. bidentata (Mont.); Spheroma? egregium (Chilt.) 
and S. algoense (Stebb.) must be referred to the genus 
Cymodocella (Pfeff.); S. orientale (Dana) is a young 
specimen of the genus Cerceis (M.-Edw.). Spheroma 
' perforatum (M.-Edw.) and 8S. globicauda (Dana) are 
probably species of Dynamenella (n. gen.); if not so, one 
of them is or both are to be referred to the same genusas 8. 
scabriculum (Hell.) (see the footnote on p. 102). Spha- 
romaJurinii (Sav.), S.Savignii (M.-Edw.),S. tristense 
(Leach), S. anomalum (Hasw.), S.asperum (Hasw.), 8. 
amplicauda (Stimps.), S. rhombura (Richardson), 8. 
octoncum (Richardson), S. plumosum (Whitelegge), and 
S. latifrons (Whitelegge) do not belong to Spheroma, 
but I cannot refer them to genera, because the descriptions 
and figures are too defective in some respects. On 8. 
Quoyanum (M.-Edw.), 8S. oregonense (Dana), 8. obtu- 
sum (Dana), S. leviusculum (Hell.),S. triste (Hell.), S. 
leve (Hasw.), S. crenulatum (Richardson), and 8. aus- 
trale (Whitelegge) I have no opinion. 
(2) Hemispheroma (n. gen.).—The type is H. pulchrum 
(n. sp.), of which I have seen an adult male and an immature 
female. To the diagnosis of the genus on p. 103 a short 
description of the species may be added. ‘The epistome has 
a rather deep longitudinal groove and two pairs of marginal 
processes ; first pair, placed near the middle of the margin, is 
low ; second pair, situated near the proximal end, is rather 
long, vertical. Antennule essentially asin Spheroma. The 
three anterior pairs of thoracic legs are moderately slender 
and furnished with a large number of exceedingly long stiff 
sete along the whole outer margin of the long third joint and 
along the distal two thirds of the same margin of fourth 
joints, besides some rather long setz on the most distal part 
of the outer margin of fifth joint. The three following pairs 
of legs are much shorter and more robust, seventh pair as 
