62 ATHERINID^ : SILVERSIDES 



96. Thyrinops pachylepis (Giinther), 1864.-5'*- 



Atherinichthys pachylepis Giinther, Proc. Zool. Soc. London, 25, 1864; Trans. 

 Zool. Soc. London, 6, 443, 1869. 

 Menidia pachylepis Jordan and Evermann, BxtU. U. S. Nat. Mns., 47, pt. 1, 



801, 1896. 

 [Thyrina] pachylepis Jordan and Evermann, ibid., pt. 3, 2840, 1898. 

 KiRTLANDiA PACHYLEPIS Gilbert and Starks, Mem. Cat. Acad. Sci., 4, 57, 1904; 



Starks, Proc. U. S. Nat. Mus., 30, 783, 1906. 

 Thyrina pachylepis Regan, Biol. Ccntr.-Amer., Pisces, 64, 1907. 

 Thyrinops pachylepis Hubbs, Proc. Acad. Nat. Sci. Phila., 69, 307, 1918. 

 Type-locality. — Panama. 

 Range. — Costa Rica to Ecuador. 



XXVI. ATHERINELLA Steindachner, 1875. 



Atherinella Steindachner, Sitzb. Akad. Wiss. Wien, 71, 477, 1875. 



Orthotype. — Atherinella panamensts Steindachner. 

 Range. — Panamaic Province. 



Atherinella is related to Thyrinops and Thyrina, but is much 

 more aberrant than either ; in fact, it is one of the most aberrant genera 

 of the Atherinid.e, being characterized by extreme features. The 

 belly throughout is carinate, not merely sharply compressed ; the rami 

 of the lower jaw are more elevated than in any other genus of the sub- 

 family ; the scales are strongly dentate ; both dorsal fins are more pos- 

 teriorly inserted than in any other member of the family; the first being 

 over the middle of the anal base. 



97. Atherinella panamensis Steindachner, 1875.-^*- 



Atherinella panamensis Steindachner, Sitzb. Akad. Wiss. IVein, 71, 477, 1875; 



Jordan and Evermann, Bull. U. S. Nat. Mus., 47, pt. 1, 805, 1896; Gilbert and 



Starks, Mem. Cat. Acad. Sci., 4, 59, pi. 9, fig. 17, 1904. 

 Type-locality. — Panama. , 



Range. — Panama Bay. 



XXVII. EURYSTOLE Jordan and Evermann, 1896. 



EuRYSTOLE Jordan and Evermann, Bull. U. S. Nat. Mus., 47, pt. 1, 802, 1896. 



Orthotype. — Atherinella eriarcha Jordan and Gilbert. 

 Range. — Pacific shores of tropical America. 



In its sharply compressed body, deep and abruptly truncated head, 

 convex interorbital. and very wide lateral band, Eurystole is remark- 

 ably convergent toward Iso, a genus of the Atiierinin.e inhabiting the 

 western shores of the Pacific. In these characters, Eurystole dififers 

 from all other genera of the subfamily Atiierinopsin.e to which it 

 belongs. From all the Atherinid.e it is distinguished by the develop- 

 ment of a weak spine, closely appressed to the head, at the angle of 

 the preopercular ridge. Eurystole seems to be at least remotely related 



