MAZATLAN UNIVALVES 421 
Tablet 1972 contains 9 sp. very young.—1973, 8 do. adoles- 
cent.—1974, 9 do. adult, various sizes.—1975, 3 do. repaired 
after fracture.—1976, 2 sp. with opercula.—1977, 1 sp. beauti- 
fully encrusted, another with broken lip shewing the fold 
within, and 2 dead sp. in which state the details of sculpture 
are conspicuously marked. 
508. CHRYSALLIDA TELESCOPIUM, 7. S. 
Chr. t. conicd, turrita, alba; vertice nucleoso, satis promin- 
ente, anfr. ii. helicoideos verticaliter sitos continente, apice parum 
monstrante, marginibus spire (testa adolescente) rectis via 
superante ; anfr. vii. normulibus, quarum v. planati, in spird, 
ut in “Chr. communi,” clathris circiter xvi. et lirulis spvralibus 
iv. decussatis : testa adolescente, lacund suturali impressa circa 
hasin continud ; peripherid angulatd, apertura subquadrata ; 
testa adultd, basi haud angulatd, effusd, haud lacunaté ; peri- 
tremati continuo, ad basin late sinuato: basi lirulis spiralibus 
circiter vil. cinctd, interstitiis vix decussatis . plied columellart 
intus acutd, prominente, ad aperturam vix monstrante, declivt. 
This species begins life as a helicoid body, rather large in 
proportion as in Chemnitzia, which genus it also approaches in 
the number of whirls. These are flat, with straight margins, 
having the basal periphery angulated in the adolescent shell, 
in which state it approaches the form of Telescopium. The 
sutural groove formed by the hollowing off of the ribs in the 
last cancellated division, is then continued round the base. In 
the last whirl however, the shell is contracted, the base pro- 
duced, the sutural groove evanescent, the aperture effuse, and 
a strong continuous labium finally appears. It is known from 
Chr. communis by the large size of the vertex, taking off the 
appearance of truncation from the shell; m the non-adult state 
by the greater angulation of the base and antesutural groove 
(the ribs in the common species not quite reaching the suture) ; 
and in all states by the greater divergence, and by the basal 
strize, which are stronger and less numerous. A specimen in 
the angular state measures Jong. ‘082, long. spir. °055, lat. *037, 
div. 30°. One almost adult measures long. °125, long. spir.~085. 
Hab.—Mazatlan ; 10 specimens (mostly young) off Chama and 
Spondylus ; L’pool Col. :—do. 3 sp. (one adult) ; Havre Col. 
Tablet 1978 contains the youngest sp., with two and a half 
normal whirls; an aigular specimen with 5 whirls ; a perfect 
sp. with 6 whirls, normal form, but without the parietal lip ; 
Dec, 1856. NN. 
