264 



SCIENCE 



[N. S. Vol. XXXVII. No. 946 



at the most, it is strongly positive to intense 

 illumination, whereas in light of low intensity it 

 remains indifferent. On that account the copepod 

 swims about close to the surface of the water 

 throughout moat of the day, with a spiral, dart- 

 like motion, which in many respects is similar to 

 the locomotion of the hunter ciliates. At night 

 it sinks to deeper regions, due to its high specific 

 gravity. These migrations are parallel with those 

 of the brook trout and are, therefore, of great 

 advantage to the life of the parasite. Increasing 

 the temperature of the water, even to a degree 

 that proves fatal, does not alter the reaction of 

 the copepod to light. Chemicals also, such as 

 sodium chloride, potassium chlorate, copper sul- 

 phate, calcium chloride, hydrochloric, sulphuric, 

 tartaric and oxalic acids cause no reversal in the 

 behavior of the copepod to light. In hydrogen- 

 peroxide, magnesium sulphate, nitric and acetic 

 acids indications of reversal were noticeable. The 

 copepod reacts quickly to pieces of gill of the 

 brook trout, but not at all to those of rainbow 

 trout. 



COMPARATIVE ANATOMY 



Alexander Petrunkevitch (Yale University) : 

 The Origin of Arachnida in the Light of Fale- 

 ontological Evidence. 

 Edwin Linton (Washington and Jefferson Col- 

 lege) : Note on a Viviparoiis Distome. 

 A distome (species not yet determined) found 

 in the cloaca of a herring gull at "Woods Hole, 

 Mass., July 22, 1912, is unique in that the folds 

 of the uterus contain ova in which active, ciliated 

 larvffi (miracidia) have developed. The larvje are 

 conspicuous on account of the black pigment eye- 

 spots. When the larvEB are set free from the 

 parent worm each is seen to contain a single well- 

 developed redia. 



So far as the early stages of distomes have been 

 observed in the marine invertebrates of the Woods 

 Hole region they show a much less complicated 

 life-history than that of the liver fluke. Sporo- 

 oysts have been found (in certain mollusks and 

 one annelid) some containing tailed, others tailless 

 cercarise. None were seen with redise. In those 

 cases the redia stage is missing. In this distome 

 from the herring gull the sporocyst stage is evi- 

 dently omitted. 



J. F. Abbott (Washington University) : Adapta- 

 tions for Air-hreathing in the Ocypod Crahs. 

 r. D. Barker (University of Nebraska) : A Con- 

 tribution to the Parasitic Turbellaria. (Lan- 

 tern slides and demonstrations.) 



While working on the parasites of the fishes at 

 the Bermuda Biological Station last summer two 

 new species of parasitic turbellaria were found in 

 the posterior sacculated portion of the intestine 

 of the Bermudian holothurian Stichopus, both the 

 black and the spotted varieties harboring the 

 parasites. 



In Bronn's "Klassen und Ordnungen des Thier- 

 Eeichs, " 1908: 2574, forty-seven parasitic turbel- 

 laria are enumerated. These are classed as ecto- 

 and ento-' ' Raumparasiten ' ' and ecto- and ento- 

 parasites; the latter are further divided into 

 ccElomie, liver, kidney and intestinal parasites. 



Parasitic turbellaria have been found in the 

 following hosts: annelids, gephyreans, crustaceans, 

 eehinoids, holothurians, lamellibranchs and gas- 

 tropods. Six species representing two genera have 

 been reported for holothurians in general and one 

 species, Anoplodium schneideri, has been described 

 by Semper as occurring in the intestine of the 

 holothurian Stichopus variegatus. With the ex- 

 ception of two species, the parasitic turbellaria sf 

 the holothurians occur in the body cavity. Not all 

 of the holothurians examined were infected and 

 in no case was the infection severe, twelve para- 

 sites being the largest number found in any one 

 host. Both species of turbellaria were found in 

 only one third of the animals examined, the larger 

 elongated parasite being the more abundant. 



The preliminary study of these turbellaria and 

 a comparison with the known parasitic turbellaria 

 shows them to be new and undeseribed species 

 and thus adds two more parasitic turbellaria to 

 the list. 



The detailed description of these forms will be 

 published soon and will be followed by a further 

 study of the histology and life history of these 

 turbellaria with the hope of settling or giving 

 new light and additional knowledge on a number 

 of points concerning trematode and turbellarian 

 morphology and histology which are now in 

 dispute. 



H. S. Pratt (Haverford College) : The Trematode 

 Parasites of the Loggerhead Turtle. 

 The parasites of the loggerhead turtle {Caretta 

 caretta) have been studied from the Mediter- 

 ranean Sea and the Gulf of Mexico. The two 

 principal localities in the Mediterranean region 

 where they have been collected are Trieste and 

 Alexandria, where a large number of the turtles 

 have been investigated for parasites by well- 

 known zoologists from the time of Rudolphi to 

 the present. In the most recent times Braun and 



