PARTULA GIBBA, SAIPAN. 109 
mitella-rubra are always yellow, (4) the castanea-rubescens are red in correspondence with 
their general ruddy coloration, save in a few exceptional instances, while finally (5) 
the castanea-purpurescens shells are usually light purple, but occasional specimens are 
red, yellow, or white. 
The degree to which the tooth is developed in the several color-classes (table 
57) does not vary significantly. The large number of mitella with a distinct but 
very small tooth is due to the prevalence of this class in the Chalankiya association 
which has a high colonial average for the structure in question. 
TABLE 57.—Partula gibba, Saipan. Statistics of lip color and tooth development. 




Color of lip. Tooth. 
Series. No. | 
Yellow, 
White. yellow- Red. Purple. None. Trace. Small. 
brown. 
PRICE OT ra) 5.0 eee 8.6.5 aes 316 316 2 ole OB abe 296 20 
USOT Oy pee 1. Sie ae 1,204 135 1,069 : a dete ee 1,102 99 3 
AS See eee See ee 631 18 613 ee ee. 495 121 15 
mutella-rubra is; ss. 6. .60-6. 156 156 Le 113 39 4 
castanea-rubescens......... 333 at ie 329 4 297 34 2 
castanea-purpurescens...... 26 1 5 2 18 23 3 
GR dats cee cnt im chor os oss bund 2,666 470 1,843 331 ZZ 2,326 316 24 




EMBRYONIC MATERIAL. 
The eggs and young taken from the adult individuals are abundant and the 
latter are particularly valuable for a problem that was difficult of direct solution 
in the case of the Guam series, namely, the question as to the mutual crossing of 
the color-classes. The collections were made late in July of 1920, when the con- 
ditions were apparently very favorable, for the animals seemed to be at the height 
of their reproductive cycle. 
The full data of fecundity are given in table 58. Of the 2,585 recorded in- 
dividuals about 85 per cent proved to be gravid, in close agreement with the Guam 
gibba, among which approximately 86 per cent were actively bearing. ‘The repro- 
TABLE 58.—Partula gibba, Saipan. Statistics of fecundity. 


























Gravid. Embryonic contents. Average for gravid. 
ee ee ee ee es See PA Ver 
F Date Rec- age 
Locality. (1920). | ords. Pp Total | for 
No. a Eggs. | Young. | Total. | Eggs. | Young} con- all. 
cent. 
tents. 
PAUPUATIMELOLES'.. S..:2 8 od os sw oars July 28 ab 226 | 82.8 454 330 784 | 2.01 | 1.46 | 3.47 | 2.87 
SACOM ASI cesee oa suede oelscpiaste July 28 412 341 | 82.8 721 BOOT 1 S220 e210 | 146) 193.57 1 2:96 
PUNtaAnVOUCHUCe sess hares» July 28 145 99 | 68.3 187 174 SOL" 1589") L276 (3.658 762'.49 
ana gan ain a sot. sc.3,ce bad) ys July 29 426 365 | 85.7 632 SAS ES HCD 8 (SR TOP i le: Soe Ps We Ae Be 
BIEL Gantt tertPetewaie teres @ aici trate ee) July 29 130 110 | 85.4 241 176 Aba Leto et OO ts. £9 | ae L 
EAStAINAN Asses»: lather > seh ok July 30 407 391 | 96.1 1,077 732 | 1,809 | 2.76 | 1.87 | 4.63 | 4.44 
Sara Dac ress apace exes ereuciede § tap July 27 269 192 | 71.4 330 309 CSO Laie aL eOlit S,ooat 2oak 
Chalankivarscern. cee. 4 July 27 523 473 | 90.4 7a GUL 90 Wa e4 ea S15 S782 3542 
SUIMMATY fetes. ote tens seer es 2 S859 2897 642090) 45613 | s,008 | 8,181 [25199 1.53 | GURL Poel G 


