“ 
MAZATLAN BIVALVES 47 
smooth lunular portion, not specially coloured. The margin 
is generally simple, nearly asin D. Conradi: and when it has 
the interealary grooves proper to D. punctatostriatus, they are 
rarely carried up into intercalary rows of dots. The epider- 
mis is remarkably thick round the margin. Colour sometimes 
white, occasionally yellow, but generally stained with rich 
reddish purple. Whether it be an aberrant variety of D. punc- 
tatostriatus, or a distinct species, must be determined when 
more specimens have been examined, or the animals studied. 
The largest but not characteristic specimen measured Jong. ‘91, 
bee VST; alt. 57: 
Hab.—Mazatlan ; very rare; L’pool Col. 
Tablet 168 contains 3 specimens, white, yellow and purple. 
76. Donax Conranti, Desh. 
Proce. Zool. Soc. 1854, p. 351.—Rve. Conch. Icon. pl. 5, sp. 29. 
+D. contusus, Rve. Conch. Icon. pl. 4, sp. 24. 
+D. Californicus, Conr. teste Desh. ms. B. M. & Col. Cuming : 
nequaquam, teste Nuttall. 
+ D. culter, Hanl. Proc. Zool. Soc. 1845, p. 14.—Rve. Conch. 
Icon. pl. 4. sp. 21. 
It is not without the most careful, laborious and often 
repeated examination of upwards of 1,000 specimens that I have 
felt compelled to depart from the views of the illustrious 
Deshayes and the very accurate Hanley, and group together. 
the species above quoted. The D. Californicus, teste Nuttall 
whose shells were the basis of Conrad’s descriptions, is very 
different from the shells so named by Desh. in the Br. Mus. 
and Col. Cuming; the former being a smooth, gibbous, sub- 
triangular shell, more like a young D. punctatostriatus, though 
quite distinct. The name Conradi is preferred to culter which 
has priority, as expressing the adult form, and as leaving 
contusus and culter for the use of those who believe in the 
species, without introducing confusion. The shells wrongly 
called D. Californicus are simply the white variety of the forms 
contusus and culter. 
This creature loves liberty both in form and colour. The 
shape is generally transverse, not unlike the large variety of 
D. anatinus, slightly swollen ventrally, with a flattening towards. 
the posterior end. Sometimes it tapers off at the anterior part, 
which is then somewhat flattened: sometimes the whole shell 
