Makch 6, 1914] 



SCIENCE 



365 



been made and some of the more important facts 

 of their internal anatomy determined. With the 

 permission of the Secretary of the Smithsonian 

 Institution, I make known some of the results of 

 this preliminary study. Helodrilus tenuis has 

 paired sperm sacs in XI. and XII. only, and has 

 no spermathecEe. It belongs to the Bimastus sec- 

 tion of the genus and is the same as H. constrictus 

 (Rosa), described in 1884. Its relation to S. 

 norvegicus (Eisen) is as yet uncertain. B. tumi- 

 dus has sperm sacs in XI. and XII. only, and has 

 no spermathecEe and hence belongs to the Bimastus 

 section of the genus as has been assumed by 

 Miehaelsen. Tetragonura pupa, now regarded by 

 Miehaelsen as simply a form of HelodriUis tetrw- 

 drus (Savigny), is represented in the collection by 

 a single specimen which, although labeled by 

 Eisen as Tetragonura pupa, has spermiducal pores 

 on XI. instead of on XII., as described by him. 

 All of the reproductive organs and the crop and 

 gizzard are four somites anterior to the position 

 normal for LumbrieidEe. There is but one pair of 

 "hearts" and they are in VII. The entire anat- 

 omy of this specimen is that which might be ex- 

 pected if a specimen of Helodrilus tetrcedrus her- 

 cynia (Miehaelsen) had lost the anterior nine 

 somites and regenerated the usual number of five 

 new ones. We do not know how many specimens 

 Eisen may have had and it is certainly unsafe to 

 assume that his description was based on this par- 

 ticular specimen. The real status of this species 

 seems as uncertain as before. (These results will 

 appear later under a different title in a more ex- 

 tended paper from the United States National 

 Museum.) 



A Study in Strongyloid Parasites of Cattle and 

 Sheep in, South Carolina: A. P. Conkadi. 

 Among the nematode parasites occurring in the 

 digestive tracts of young cattle and sheep in 

 South Carolina, the stomach worm, Swmonchus 

 contortus and the hookworm of cattle, Monodontus 

 phleiotomus axe very important. An extended 

 study of these parasites was made covering a 

 period of several years. The stomach worm oc- 

 curs in both young cattle and sheep in injurious 

 numbers. Hookworm has not been found in- 

 jurious in sheep, but among cattle this is a spe- 

 cies to be reckoned with. The life history of the 

 two species is very similar. The eggs are laid in 

 the stomach and after passing from the animal 

 hatch in from three days to several weeks, de- 

 pending on the temperature. In our work the 

 stomach worm was almost altogether confined to 



the fourth stomach, while the hookworm was con- 

 fined to the upper eight feet of the intestines. 

 While the hookworm fastens itself to the intestinal 

 wall and sucks blood, we were unable to prove this 

 in case of the stomach worm. These occur in the 

 mucous secretion between the mucous membrane 

 of the stomach and the ingesta and are very rarely 

 attached. Even when the specimen is attached it 

 is but feebly so and can be removed, while in the 

 case of the hookworm often the head is torn off 

 when trying to remove it with the forceps. A vul- 

 nerable point in the control of both species lies 

 in the fact that moisture is absolutely necessary 

 for the egg and young larval development. This 

 is true in the laboratory, and experiments in the 

 field have shown that this point can be taken ad- 

 vantage of. A heavily infested lot being about 

 one half creek bottom and one half hillside was 

 divided so as to separate the lowlands from the 

 highlands. An equal number of calves of the 

 same age were placed on these lots in the early 

 spring and these animals received the same amount 

 and kind of feed, except that those in the lower 

 lot obtained their water from a running brook. 

 At the end of the season we had 62J per cent, 

 more calves on the upland than on the lowland. 

 The following year all calves were kept on the up- 

 land and no death occurred. In our work the 

 heaviest egg record occurs during June and July, 

 while the death rate begins the latter part of Au- 

 gust and continues through September and Oc- 

 tober. In our work no young calves born after 

 August 25 took the disease, while the parasites 

 left infested animals at from ten to fourteen 

 months of age. 

 On the Whale Shark, Bhineodon typus: F. W. 



GUDGEB. 



The Eruption of the Permanent Teeth: Egbert 



Bennett Bean. 



Data for 2,221 school children. The eruption of 

 the permanent teeth in the Filipinos is from one to 

 four yeai's earlier than in the Germans and Amer- 

 icans; females are more precocious than the males 

 in all three groups. The lower permanent teeth 

 erupt before the upper ones, except that the upper 

 premolars erupt before the lower. 



The teeth erupt in the following order: (1) 

 Lower first molars; (2) lower median incisors; 

 (3) upper first molars; (4) upper median incisors; 

 (5) lower lateral incisors; (6) upper lateral in- 

 cisors; (7) upper median premolars; (8) lower 

 canines; (9) lower median premolars; (10) 

 upper lateral premolars; (11) upper canines; (12) 



