241] TURBELLARIA FROM THE MISSISSIPPI BASIN— HIGLEY 47 



In size and shape my specimens are very nearly those of the eastern form 

 but the color is strikingly different. Altho showing a sepia-brown when the 

 animal is compressed to such an extent that the parenchyma is a thin layer, 

 yet under ordinary conditions it is very dark. It appears evident that the 

 pigment cells when fully developed lie so close together as to aggregate in a 

 color nearly black. It is really a duU brownish-black, so opaque as to obscure 

 entirely the internal organs. On account of this color in the parenchyma, the 

 integument by contrast is exceedingly prominent. It is especially thick and 

 possesses an almost iridescent transparency. It so reflects the light as to show 

 the convexity of the body surface. This gives an appearance of solidity not 

 present in most specimens. The ciha are fine, clear, and very swift and heavy 

 in their motion, as a result of the lack of a strongly functional muscular system. 

 The parenchjona is composed almost entirely of pigment-bearing cells. That 

 is, there is no layer of colored cells on the outside just beneath the integument 

 as is commonly the case, but most of the parenchyma cells contain more or 

 less pigment substance so that the color is scattered. The fluid material is pre- 

 sent but it is not conspicuous. In shape, the cells are irregular and in most 

 respects they resemble the parenchyma of other forms. The digestive tract 

 is different from the type only in minor details. So covered by the pigment 

 that it is not apparent until crushed out from the surrounding tissues, it shows 

 the characteristic green of the wall cells. The pharynx apparatus is especially 

 long, extending back thru more than one-third the body length. The anterior 

 vestibular portion is shorter than the pharynx proper, but is of about the same 

 diameter. The papillae on the surface of the vestibule are very slender and 

 lie far apart. 



The only point of note in regard to the reproductive organs is the duct 

 leading from the uterus to the genital pore. This is extremely slender and 

 long, a mere thread reaching up into the body mass for a distance almost equal- 

 ling the main diameter. In specimens where the egg is very large and ready 

 to be laid, the duct appears almost incapable of such extension as must be 

 necessary. The yolk glands, testes, and ovary lie embedded in the parenchy- 

 ma. 



It seems probably that this species feeds upon the minute algal growths 

 in the filamentous masses where it habitually lives or upon plant debris just 

 below on the surface of the mud. It presents a type of structural detail very 

 different from most other species. 



Dalyellia alba nov. spec. 

 Figures 24 and 26 



The habitat of this species presents conditions very nearly like those of most 

 ponds. A muddy bottom, with roily dark water, some amount of leaves 

 and other organic debris and much floating Cladophora make a surrounding 

 environment suitable for rhabdocoel types. Chief among these is Stenostoma 

 leucops. The DalyeUias are always taken from masses of algae. They appear 



