THE MYSIDACEA 



'i'll 



beyond the eye ; in Boreomysis scyphops the distal end of the peduncle 

 is expanded .and excavated in a cup -like form and is without 

 pigment or any trace of ocular structure, but in other species of 

 the same genus the eyes are normally developed ; in some Petal- 

 ophthalmidae the peduncles are leaf-like or spiniform ; while in 

 Fseudomma, Amhlyops, and some allied genera, they arc repre- 

 sented by broad plates extended 

 horizontally in front of the carapace. 



In the ]\Ivsi(lae the three-seg- 

 mented peduncle of the atifeiinnles 

 carries in the male sex, in addition 

 to the two flagella, a conical process 

 beset with numerous sensory fila- 

 ments. 



The anteiuiae have the protopodite 

 distinctly composed of three segments 

 (Fig. 101, 1, 2, 3). A lamellar ex- 

 opodite or " scale " (sc) is always 

 present except in Arachnomysis and 

 allied genera, where it is represented 

 by a spine. In many jMysidae it is 

 divided into two segments by a trans- 

 verse suture near the tip. 



The mandibles have generally a 

 well -developed lacinia mobilis (Fig. 

 102, l.m), differing in form on the 

 two sides, and a row of spines (s) in- Pi^, ;im 



terpOSed between the incisor and Cephalotlioracic region of Jl/i/.-tisrc/ic/fr, 



innl'ir nrnppsstspq Thp row nf sninpq you"g. female, from below. Most of the 

 mOiai processes. J. ne 1 0\\ OI bpineb thoracic appenda-es have been removed. 



is absent in the Lophogastridae and «'> external flagellum of antennule ; V" 



^ ® . flagellum of antenna ; ex, exopodites of 



EuCOpndae and some JNlySldae, and thoracic appendages ; l, labrum ; mil, palp 



.1 1 • • 1 -T • of mandible ; 0, oostegite.s, not vet fiillv 



ni some cases the lacuna moblllS is developed ; »■, scale or exopodlte of an- 



wTnfincr Tlip mnlnr nrnr-pss is <^mall tenna ; thi-th 3, lir.st, second, and third 



Wanung. ine moiai piOCeSSlS bmau t,ioracic appendages; 1, ■_', 3, the three 



or absent in a few JMysidae. A palp segments of the protopodite of the an- 



, , "{ '^ T tenna. (After Sars.) 



IS always present, and becomes greatly 



enlarged in the aberrant PctalophtlMhims, Avhere it appears to have 



a prehensile function. 



The 'miLrilluliU' (Fig. 103, A) have two endites arising, according 

 to Hansen, from the first and third segments, and a slightly 

 developed laminar exite, which Hansen states belongs to the first 

 segment. In the genus Gnathopliavda (Fig. 104) a palp of two 

 segments is present, directed backwards beneath the carapace like 

 that of the Leptostraca. 



The maxillae (Fig. 103, B) have a complex structure. There 

 are two endites corresponding to the second and third segments 

 (Hansen), the first of which is incompletely and the second com- 



