Guadeloupe. The white shrimp is extremely rare 

 iu that general area ; scarcity of brackish waters, 

 or high salinity and unsuitable bottom may be 

 responsible for the failure of the species to estab- 

 lish around those islands, where P. a. suhtUis 

 and P. hrmiliensls are common. 



This white shrimp is rather restricted within 

 its range. Not only are there broad stretches 

 where it seems to be absent ; it also exhibits a dis- 

 junct distribution within rather small areas. In 

 my intensive sampling for Penaeus in the waters 

 around Cuba, both P. schmittl and P. duo m rum 

 notlalis were found to be rather abundant. Tlie 

 latter lives in many localities around Cuba, but 

 the white shrimp is restricted to certain areas. On 

 the south shore, for instance, white shrimp is 

 absent west of Bahia de Cienfuegos, and from the 

 entire Golfo de Batabano to the westernmost tip 

 of Cuba. The dense concentrations of this species 

 that are fished intensively are in relatively shal- 

 low water. In Cuba, white shrimp are found in 

 large numbei-s to depths of 12 fm., and in the 

 waters of the Gulf of Venezuela, they are abun- 

 dant as deep as 10 to 14 fm. Although P. schimttl 

 in most areas is found in water not deeper than 

 15 fm., off the coast of Honduras it is fished in 

 depths between 11 and 20 fm. (I^oesch, 1962), and 

 Bullis and Thompson (1959b) caught a few speci- 

 mens in water 15 to 26 fm. deep, off the northeast 

 coast of South America. The reported (Anony- 

 mous, 1961) catches in 150 to 200 fm. off the 

 western edge of Great Bahama Baitk have not 

 been authenticated; if this species does live in 

 that area it is likely that the shrimp that ap- 

 peared in this deepwater haul entered the net as 

 it approached the surface. 



My detailed studies of representative samples 

 from many areas indicate little geographic varia- 

 tion in the diagnostic characters of P. schmltti 

 throughout its range. I have been unable to rec- 

 ognize any significant differences between the 

 population of the Caribbean Sea and that of the 

 Atlantic, or throughout the latter population. 



Although my data (fig. 19) and those of Ewald 

 (1965c) seem to indicate tliat a change in the 

 relation between carapace length and total length 

 occurs at the time the white shrimp reaches about 

 21 to 22 mm. c.l., Garcia Pint« (1965) found two 

 discontinuities instead of one in that relation — 

 one at a smaller and the other at a larger size. 



Relationships 



P. schmittl has close affinities with P. setifenis. 

 Females, however, may be distinguished by the 

 two rigid, rounded posterior protuberances on 

 somite XIV and the two anterolateral ridges that 

 are almost j^arallel. The ridge at the posterior 

 margin of somite XII also has typical shape, bear- 

 ing two pairs of large convexities on each side, 

 the lateral being the larger. Males of P. schmittl 

 have the distomedian corner of the lateral lobe 

 of the petasma produced in a characteristic sub- 

 rectangular projection, with the inner surface 

 lacking a diagonal ridge. The crest located nearer 

 the ventral margin on the outer surface of the 

 lateral lobe is also typically bifurcate instead of 

 plain. In the original description of P. schnvittl, 

 Burkenroad considered the contour of the margin 

 of the pleuron of the first pleonic somite a diag- 

 nostic character, but I have found the contour un- 

 reliable, for its shape varies over a wide range. 



Reproduction 



SUBADULT STAGE-SEXUAL MATURITY 



The minimum size of males with joined petas- 

 mal endopods is 21 mm. c.l., 100 mm. t.l. — ap- 

 parently the smallest size at which males reach 

 the subadult stage. The joining of the petasmal 

 endopods occurs, however, within the size range 

 21 to 27 mm. c.l., 100 to 126 mm. t.l. In both P. 

 schmltti and P. setiferus the petasmal endopods 

 join at a lai'ger size than in the grooved Penaeus. 



Thus far, it has not been possible to determine 

 accurately the minimum size at which females are 

 capable of being impregnated, although, accord- 

 ing to my observations, the thelycum seems fully 

 developed at 21 mm. c.l., 100 mm. t.l. The min- 

 imum size at which females of this species reach 

 sexual maturity is not known. 

 COPULATION 



As it seems to be true in other Penaeus with an 

 open thelycum, copulation in P. schmittl is be- 

 lieved to take place between hard-shelled indi- 

 viduals. The smallest females that have been found 

 impregnated were 30 mm. c.l. The spermatophores 

 are attached to the thelycum by means of the 

 anterolateral wings, the triangular stiiicture on the 

 [josterior margin of each wing, and the postero- 

 dorsal extensions. The glutinous material that 

 surrounds the spermatopliores when extruded aids 

 in holding tliem temi)orari]y to the thelycum. The 

 coxae of the fourth and fifth pereopods of the 



WESTERN ATLANTIC SHRIMPS OF GENUS PENAEUS 



495 



