380 TAGE SKOGSRERCr 



Maxilla: — End joint: The bristles of this joint, as will be seen from what has been 

 said above, also show an exceedingly close agreement with regard to their position with the 

 bristles of the corresponding joint in the sub-family Cypridininae. On account of this there 

 can scarcely be any doubt that there is real homology present. In this case too I have thought 

 myself justified in using a similar alphabetical notation, based on homologization, for these 

 bristles as for those of the sub-family just mentioned. The group whose (three to five) bristles 

 form a transverse row on the outside of this joint are consequently denoted as a-bristles, the 

 group (two) distally-anteriorly = b-bristles, the group (three to five) distally-medially = 

 c-bristles and the remaining bristles, situated postero-distally on this joint — d-bristles. 



Fifth limb: — With regard to the homologization of the bristles on the second 

 exopodite joint I merely refer to what has been written above in the description. 



The ciassijicatioii Reniurks: — The five species of this genus that have been described in this work certainly 



form quite a natural classificatory unit. 



One of these forms. Ph. Appellofi, is, however, opposed to the others in some characters, 

 especially by its strongly marked shell sculjDture and its jointed rod-shaped organ. On account 

 of this it seemed convenient to distinguish this species as a representative of a new sub-genus, 

 which has been given the name of Scleroconcha. 



Of the species of this genus dealt with in the literatui'e it is rather certain that three 

 others belong to this sub-genus, viz.: 



Ph. Folini, G. S. Brady, 1871, p. 294, pi. XXVII, figs. 1—5. 

 „ sculpta*, „ „ „ 1898, p. 434, pi. XLIV, figs. 1.5—20. 

 „ flexilis, „ „ „ 1898, p. 435, pi. XLIV, figs. 1—14, pi. XLV, figs. 15, 16. 



All these three forms are characterized by a very powerful shell sculpture, developed in the 

 form of extensive ridges. At least two of tliem. Ph. Folini and Ph. flexilis, have, in addition, a 

 jointed rod-shaped organ of the same type as Ph. (Scl.) Appellofi. In Ph. sculpta, unfortunately, 

 this organ is unknown. — It does not seem impossible that another species. Ph. Wyville- Thomsoni, 

 G. S. Brady, 1880, p. 160, pi. XXXVI, fig. l, a — c, is to be referred to Scleroconcha too. Because 

 of the incomplete description — this species is referred by G. W. MtJLLER, 1912, to ,,C}^ridinidarum 

 genera dubia et species dubiae" — nothing, however, can be said with certainty about it. 



With regard to the mutual relations of the other species referred to this genus it is still 

 too early to make any definitive statement; the descriptions are generally, imfortunately, too 

 incomplete. It will probably be necessary — even after distinguishing Pleoschisma and Tetragonodon 

 as special classificatory units, cf. p. 348 above — to carry out a further division; I need only 

 point out here that such aberrant forms as Ph. longiseta (-H. Jijday and Ph. loniae C-H. JudaY 

 certainly cannot be retained in this genus. 



Detailed diagnoses of the two following sub-genera may conveniently be postponetl 

 until a greater number of species of this genus have been subjected to a closer re-examination. 



* This species is, hesitatingly, idoalifiod liy G. S. Bradv hiiiiS'U, 1898, p. 'iZa as Sireploleberis rreiiulala,G. S. Brauy, 

 1890, p. .515. This identification demands too much, however, from the inexactitude of the two descriptions to he 

 adopted a priori. Of course its correctness is not absolutely impossible 11 — It does not seem to me impossible that 

 Ph. sculpta and Ph. jlcxilis are male and female of the same specie.s. 



