EEPOET ON THE AMPHIPODA. 269 



and Dana himself notices the resemblances. The species assigned are Sijnopia ultramarina, 

 (with the suggestion that one of the forms figured may be a distinct species to be called 

 Si/nojna ijradlis), and Sijnoina angusfifrons ; in the former he speaks of the eye as single, 

 occupying " the whole breadth of the triangular head," but in the latter species he speaks of 

 " the eyes " in the plural. Bovallius, in 1886, makes the " Amphipoda Synopidea " a separate 

 tribe, in which "the first family, Synopidaj, is the most closely related to the Gammarids." 

 In Family II. Phronimidaj, Subfam. 1, Phroniminre, contains only Phronima atlantica, Gu6riii, 



not figured, the brief notes indicating that Phronima sedentaria, Forskal, is in question. 

 Subfam. 2. Phrosinime, contains Ancliijlomem 2nirpurea ; Ancliylomera thyropoda, "length, 



one line; specimen probably not mature"; Themisto antarctica. 

 Subfam. 3. Phorcinfe, contains only Fhom/f' hyalocephalus, on which Dana remarks, "This 

 species has most of the characters mentioned for M.-Edwards' Phorcus Baynmidu : but, he 

 observes, that the antennas are 'un peu renflees vers le milieu'; while, in this species, 

 the basal portion is stout eUipsoidal. Moreover, he states, that the second thoracic ring 

 is very much developed, and the fifth pair of legs is shorter than the sixth." 

 In Family III. Typhidw, Subfam. 1. Typhinw, begins with the genus Dithyms, with the foUovcing 



addition to the definition : — 

 "Abdomen ad ventrem optime claudens. Caput transversum, pigmentis non grandibus. 

 Antennae 2da3 sub capite celataj, breves, non replicatie. Pedes 6 postici coxis latissinK',- 

 clypeati, parte pedum reliqua ohsoleta. Pedes 4 antici subcheUformes. Abdomen .5- 

 articulatum, segmento ultimo triangulato." In the appended remarks Dana says, "the 

 abdomen, unlike that of Tliyropus, is shorter than the thorax." This genus is identified 

 by Glaus with Typhis, Eisso, and as Typhis is preoccupied, Dithyrus (not EidypMs, Claus), 

 takes its place. The species for which Dana instituted the genus is called Dithrjrus faha. 

 The genus Tliyropus receives the additional definition : — 



" Abdomen ad ventrem claudens. Caput transversum. Pigmenta oculomm non grandia, 

 quatuor. Antennx 2dee longx, sub thoracis latere celatce, 4-5-plicatx, articulo Imo multo 

 Ireviore quain 2d us. Pedes 6 postici co.vis late rhjpeati, artiadis reUquis paido abbreviati." 

 Eemarks are appended to distinguish the genus from Typhis, together with the statement 

 that, "this genus includes the Typhis fer ox of Edwards, Crust., iii. 96." Yov ferox, feriis 

 should be read. The type-species is Thyrojius diapihanus. Claus, Platyscehden, 1879, 

 considers that Typhis ferus probably belongs to his genus nemUyp>his ; on the other thi-ee 

 genera he says there can be no doubt, "dass Dithyrus und Typhis bei Dana ledighch als 

 weibliche Formen zu Thyropus als dem miinnlichen Typus zu beziehen sind," loc. cit., p. 7, 

 and he gives the heading, " Eutyp)his= Typhis, Eisso, [Thyropus, Dana, Sp. Batec? = 

 Dithyrus Dana 9, Platyscolus Sp. Bate ?)," but he further says, " Die Untersuchmig 

 einer grossen Anzahl kleinerer und grosserer Typhiden aus sehr verschiedenen Meeren 

 hat mich davon uberzeugt, dass Charakterisirimg der Gattungen auch nach Beseitigung 

 der durch die sexuellen Verschiedenlieiten veranlassten Irrthiimer viel specieUer gehalten 

 werden muss, und dass in der Edward'schen Gattung Typliis, dem Z*a?ia'schen Thyropuis, 

 eine Eeihe von Gattungen enthalten sind." p. 9. At p. 17 he suggests that Thyropus 

 diapjhanus, Dana, may be the same as his own new species, Tanyscelus spjhsroma. 

 Subfam. 2. Pronoinse, contains Pronoe brunncti, which may, in Claus's opinion, be the same as 

 bis Eupronoe armata, and Lycxa ochracea, as type-species of Lycxa, the following addition 

 being made to the definition of that genus : — 

 "Pigmenta ocrilorum grandia. Antennx 2dee sub capite celatx et replicatx et flagello longivs- 

 eulo con/ectx. Pedes 4 antici subcheUformes, reliqui mediocres ; 2 ultimi breviores ; coxif 

 sexposticx angustx. Abdomen in ventrem se non fectejis." 

 Claus, 1879, agrees with Spence Bate that this definition scarcely suffices to distinguish Lyrsea 

 from Pronoe, but for independent reasons he considers Dana's genus fully tenable. 



